Discharge printing of cellulose acetate



manner.

Patented Oct. 2, 1945 George W. Seymour and Victor S. Salvln,Cumberland, Md., assignors to Celanese Corporation of America, acorporation of Delaware No Drawing; Application February 28, 1942,

. Serial No. 432,750

14 Claims. (on. M

This invention relates to improvements in the discharge printing oftextile materials and relates more particularly to improvements in thedischarge printing of fabrics made of. or containing cellulose acetate,or other organic derivatives of "cellulose, which have been dyed withazo dyestuffs.

An object of our invention is the discharge printing of textilematerials and particularly fabrics made of or containing cellulose.acetate or other organic derivative of cellulose which are dyed withcertain azo dyes to obtain clear white discharge patterns.

Another object of our invention is the discharge printing of said dyedfabrics so as to obtain'clear white discharge patterns as well asilluminated discharge patterns in but a single operation.

Other objects of our invention will appear from the following detaileddescription. The discharge printing of textile materials is widely usedin the dyeing art for obtaining pattern effects on fabrics in a simpleand economical Generally, the fabric which is to be printed is dyed inthe piece in a solid color, by means of a suitable dyestuil, to providethe color desired as the background. When the fabric is dyed with an azodyestufl', a chemically active discharge paste having a reducing actionon the azo dyeforming the background color is applied locally to thefabric in a predetermined pattern,

I and the fabric then treated so that the azo dye is reduced and thebackground color is removed at the points where the paste has beenapplied,

ground. The pattern should preferably have a clear white color. Withmany azo dyestuffs clear white discharges can not be obtained regardlessof the discharging agent employed. In the case of fabrics dyed withsqme'azo dyestuffs, however, clear white'discharge patterns may beobtained, but only by employing certain discharging agents zincformaldehyde sulfoxylate. When attempts are'made to discharge these azodyes with discharge agents of alkaline reaction the pattern ob- I tainedafter the application of the discharging agent is either spotted, or isof an elf-shade of duction and is itself a dye for the fabric or onewhich can be reversibly oxidized after being vatted to the leuco form.In general, it is the vat dyes whichare used for illumination sincethese dyestufls are capable of being reversibly oxidized after beingvatted. The vat dyestufls yielding a pattern or design upon a coloredbackare applied. to the fabric mixed in with the discharge paste and theresulting paste applied in any pattern desired. The vat dyestuffs,however, must be suiliciently solubilized in the discharge paste sothatthey can penetrate the fabric properly and will give, on subsequenttreatment, even and permanent colorations. To solubilize the vat dyesproperly, the discharge paste must be alkaline in reaction since the vatdyes can not be action. In the latter case, that is, in the prepa-'ration of illuminated discharge prints, alkaline discharge agents mayfrequently be employed even though they do not discharge the azobackground color to a pure white. This is so because the illuminatingvat color may frequently mask the off-white color of the discharge afterthe vat dye is oxidized to the coloredform from the colorless leucoform. If the illuminating color is of a sufllci ently dark shade, or theelf-white shade of the discharge is light enough so as not to aflect theilluminating color objectionably, the illuminated discharge printobtained by employing an which are acid in reaction, such as, forexample,

white, having a brownish, pinkish or other .undein color instead ofwhite, that is, an illuminated an-alkaline discharging agent could notbesat- I isfactorily eflected. r c

We have now discovered thatboth white-and illuminated discharge printsmay be obtained in a single operation with alkaline; discharging agentsontextile materials dyed with, azo dyes obtained by diazotizlng an aminocompound of 'I the following general formula:

NOr-QNH:

- halogen wherein the halogen may bev Br, Cl, F oil, and

coupling said diazotized amino compound with Thus, when dischargeprinting textile maing general iormula:

2 a coupling component comprising a substituted di-hydroxyalkyl-aminocompound of the followwherein R is a hydroxyalkyl group containing atleast two carbon atoms, R. is an alkyl group, and X may be H, alkyl,O-alkyl or O-alkylene-OH. By employing azo dyestuffs of this group for.the dyeing of textile materials made of or containing organicderivatives of cellulose, such ascel- 2,385,885 K ish gum or any of thecommercially prepared gums, and swellingagents or penetrants for thematerial are added. Such swelling agentsinthe case of cellulose acetatematerials, are the thiov cyanates of sodium and potassium and 'the-penetrants may be liquids such as ethyl alcohol, glycol, thio-diglycol, etc.

The discharge paste may ric by-means of embossed or engraved rollers. bystencilling, or with blocks, orby other suitable means and the Iabriccanthen'be dried by passing through a drying tower or over heated luloseacetate, or synthetic linear polyamide condensation products, such asnylon, or other textile materials, it is possible to obtain thesematerials dyed with background colors in many valuable shades oifgblue'.depending upon the particular components coupled, and to obtain whiteand colored illuminated discharge prints on such materials bydischarging the'ba'ckground color with alkaline discharging agents. Asexamples of suitable alkaline discharging agents which maybe employed inour process there may be mentioned sodium sulioxylate formaldehyde andthe sulfoxylate formaldehydes of calcium, barium, magnesium orstrontium.

The substituted di-hydroxyalkyl-amino coupling components which may beused in the prep- The dyes may be formed in substance by the usualdiazotization methods and-the material may .be dyeddirectly in a;bathcontaining the desired amount of 'dyestuii dispersed therein by means ora suitable detergent or dispersing agent.

In some instances,.the material'whichisto be .dyed may be based with theamino compound and the diazotization and-coupling, carried out on thematerial itself. The amino compound may tionubecarried out at. a lowtemperature, pref-' erably below .C., and it may be carriedout Aftercans or drums. I

, The portion or the fabric to be discharged to a white color is printedwith a discharge paste composition free. of the vat color while'that'por-' tion which is to be illuminated is printed with a dischargepaste having the desired vat color incorporated therein. 'Byselectingthe proper combination of rollers, stencils, etc.', a printhaving two, three or even more colors-may be pre--v pared. Since analkaline dischargeagent is'em-.

ployed on both the area to be-discharged to a white color and on thearea to be illuminated,

the pattern can be so chosen that the respective colored and whiteportions are in close contact and even in overlapping relationshipwithout any danger of undesirable'chemical reactions takin place betweenthe respective areas, with the consequent formation of degraded materialin which the pattern is poorly defined. The latter was a disadvantage'which resulted, whenemploying an acid and an alkaline discharging agentin different portions of the pattern which were in fairly close contactsince this causes the edges of the patterns to creep-and destroys thesharpness and clarity of the resulting print. In addition, the fact.that acid discharging agents are not present is especially advantageouswhen producing discharge .patternswn mixed fabrics containing yarns ofregenerated cellulose, since the strength of such yarns is adverselyaffected by the action of many discharging agentswhich are acid inreaction.

be applied to the material in the form of dis- 1 ipersions or, by bathor mechanical impregnation methods, such as padding or printing.

the amino compound has been applied to the material, it may bediazotized in'the usual manner using sodium nitrite and sulfuric-orhydrojchloric acid. It is preferable that the diazo'tizaj on a winchorjig or other suitable" device for working the material. The couplingreaction may thencbecarried out by entering the treated -material'in abath containing the coupling com- .ponent; Thus, the material canbeentered into a cold coupling bath which may then beheated, i or thematerial can be v entered into a bath already In formulating thedischarge paste Q heated to about the desired coupling temfieraj ture..When the coupling is completed, the dyed 7 material'is scoured, rinsedand dried. x j

the alkaline discharge agent and the vat dye in the re- 'ducedyforin aremixed with asuitable thickenin agentsuch as gum arabic, gum tragacanth,Brit-' j After'dr'ying, the printe fabric is passed throughan ager sothat the back round colorwill be acted upon by the discharging agent inthe paste and the color destroyed. The continuous ager or cottage agerma .be used and the ageing is 'generallycarried out at about 98 C. to100 C. for a period of time suflicient to discharge the azo dye; Thisperiod may be from 1 0-t'o 20 minutes depending on the type oitab- 'ric,the particular-dyestuffs used and the depth of shade.- The fabric isthen washed to remove the decomposition products as completely aspossible and to wash out the. alkaline solubilizing agent so that theinsoluble leuco vat dye is preipitated. The vat dye' maythen-be oxidizedfrom the leuco form by exposure to air or by an oxidizing bath. After afinal wash with ,water thefabric is dried.

While our invention-is applicable to h di charge printing of varioustextile materials dyed with the class of dyes heretofore described, itis oi particular importance with respect to fabrics "or other textilematerial made of ,orcontaining yarns or filaments of silk, wool, organicderivatives oicellulose, such as cellulose esters and cellulose 'ethers,and textile materials comprising synthetic linear polyarnidecondensation products, such as nylon. Examples of cellulose esters arecellulose acetate, cellulose propionate, cellulose butyrate, and mixedesters such as cellulose acetate propionate and celluloseacetate-mityrbe applied to the fabate, while examples of celluloseethers are ethyl cellulose and benzyl cellulose. Mixed materialscontaining two or more of the aforementioned textile materials togetherwith other textile materials such as regenerated cellulose may likewisebe discharge printed in accordance with our invention. h

In order further to illustrate our invention but without being limitedthereto the following examples are given:

Example I A cellulose acetatefabric is dyed in a medium blue shade with2% of 2'-cyano-4-nitro-6'- brom benzene azo-2-dihydroxyethyl-amino-4-acetylamino-anisole. The fabric is-then printed in a suitable patternwith a discharge paste made up as follows:

v Parts by weight Sodium sulphoxylate formaldehyde Sodium thiocyanate r10v Supertex gum 45 Water 35 The printed fabric is then dried and agedin the rapid ager for 14 minutes at 100 C. The reduction products areremoved by treating the fabric for 2 minutes in a 2 gram per litersolution of NaOH and the fabric is washed, rinsed and dried. A sharpwhite design on a medium blue background is obtained.

Example If Sodium thiocyanate 6 Gum tragacanth paste 50 Water 38.-

For the green effect:

* Parts by weight Sodium sulphoxylat'e formaldehyde 4 Sodium thiocyanate4. Soda ash- 4 Supertex g .41 Water 32 Ponsol Jade Green (Color Index1101) 3 Ponsol Flavone G0 (a vat dye) 8 Indanthrene Golden Yellow GK,(Schultz Farbstoiftabellen, 7th, vol. 2, P ge 130) 4 For the red effect:

. Parts by weight Sodium sulphoxylate formaldehyde 6 Sodium thiocyanate.6 Caustic soda 4 Sulphanthrene Pink F (a vat dye) Superte g m 45 Water24 The printed fabric is then dried and aged in a rapid ager for 14minutes at 100 C. The fabric lustration and that many variations may bemade.

therein without departing from the spirit of our invention.

Having described our invention, what we de- I sire to secure by LettersPatent is:

1. Process for the production of white discharge. printing eflects upona textile material dyed with an azodyestuif formed by diazotizing anamino compound of the following general formula:

NO NH:

. Halogen and coupling said diazotized amino compound with adi-hydroxyalkylamino compound having the following formula:

wherein R is a hydroxyalkyl group containing at least 2 carbon atoms; Ris an alkyl group and X is a member of the group consisting of hydrogen,alkyl, O-alkyl and O-alkylerie-OH, which com prises applying to saiddyed material in a predetermined pattern a discharge paste comprising asulfoxylate formaldehyde discharge agent having an alkaline reaction. I

2. Process for the production of discharge printing effectsupon atextile material dyed with an azo dyestuif formed by diazotizing anamino compound of the following general formula:

i and coupling said diazotized NO NH:

alogen a di-hydroxyalkylamino compound having the following formula:

wherein R is a hydroxyalkyl group containnig at least 2 carbon atoms, Ris an alkyl group and 'X is a member of the group consisting ofhydrogen;

alkyl, O-alkyl and O-alkylene-OH, to obtain a multicolored patternhaving both'white and illu-' is then washed in 2 gram per liter causticsoda cold for 2 minutes and the vat colors are then oxidized by atreatment in 5 gram per liter sodium perborate and 1 gram per liter soapfor 2 minutes at 50? C. The fabric is then rinsed and dried. I I

It is to be understood that the foregoing detailed description is givenmerely by way, of ilminated areas,which comprisesapplying to said dyedmaterial in a predetermined pattern a plurality of discharge pastecompositions, each comprising a sulfoxylate formaldehyde discharge agenthaving an alkaline reaction and all but one of said compositions havinga vat dye in the leuco form incorporated therein.

3. Process for the production of white discharge printing effects upon atextile material compris ing an organic derivative of cellulose dyedwith an azo dyestuff formed by diazotlzing an amino compound ofthefollowing general formula:

amino compound with with a di-hydroxyalkylamino compound having the,following formula:

N(R)! 7 l NHC-T-R wherein R is a hydroxyalkyl group containing at.

least 2 carbon atoms, R is an alkyl group and! is a member of the groupconsisting of hydrogen, alkyl, O'-alkyl and O-alkylene-OH, whichcomprises applying to said dyed material in a'preder termined pattern adischarge paste comprising a sulfoxylate formaldehyde discharge agenthaving an alkaline reaction. j

4. Process for the production of discharge printing effects upon' atextile material comprising an organic derivative of cellulose dyed withan azo dyestufl. formed by diazotizin'g an amino compound of thefolowing general formula:

NO NHi alogen and coupling said diazotized amino compound with adi-hydroxyalkylamino compound having the following formula:

. wherein R is a hydroxy alkyl group containing at 'least'2 carbonatoms, R is an alkyl group andX is a member of the group consisting ofhydrogen,

. 2,886,885 "and coupling said diazotized amino compound comprisesapplying to said dyed material in a predetermined pattern a dischargepaste comprising a sulfoxylate formaldehyde discharge agent having analkaline reaction.

6. Process for the production of discharge printing effects uponatextile material comprising cellulose acetate dyed with an ago-dyestuflformed by diazotizing an amino compound of the following generalformula:

NO NH:

. Y 7 halogen and couplingsaid' diazotized amino compound with adi-hydroxyalkylamino compound having the following formula:

wherein R is a hydroxyalkvl group containlngat least 2 carbon atoms, Ris an alkyl' group and x alkyl, O-alkyl and O-alkylene-OH, to obtain a,

multicolored pattern having both white and illusminated areas, whichcomprises applying to said dyed material in apredetermined pattem aplurality of discharge paste compositions, each comprising a sulfoxylateformaldehyde discharge agent having an alkaline reaction and all but oneof said compositions having a vat dye in the leuco form incorporatedtherein.

' 5. Process for the production of white discharge printingeflects upona textile material comprising cellulose acetate ,dyed with an azodyestui! formed by diazotizing an amino compound of the followinggeneral formula: v

' NO 'Nn,

.halogen and coupling-said diazotized amino compound with adi-hydroxy-alkylamino compound havin 'the following formula: p I x 7New.

I NH W RI or whereinR is'a hydroxyalkyl group containing at I least 2carbon atoms, .R. is an alkyl group and X is a member of thegroupconsisting of hydro- Jgen, alkyl, Q-allwl and O-alkylene-OH, which:

is a member of the group consisting of hydrogen. alkyl, O-alkyland-O-alkylene-OH,- to-obtain a multicolored pattern having both whiteand illuminated areas, which comprises applying to said dyed material ina predetermined pattern a plurality of discharge paste compositions,each comprising a snlfoxylate formaldehyde discharge agent having analkaline reaction and all' but one of said compositions'having a vat dyein the leuco form incorporated therein.

7, Process for the production of white discharge printing effects upon atextile material dyed with a dyestuff prepared by diazotizing 2-cyano-4-nitro-6-brom-aniline and coupling said diazotized amine, with2-di-hydroxyethyl-amlno-'i-acetylamino-anisole, which comprises applyingto said dyed material in a predetermined pattern a dis- -charge pastecomprising a sulfoxylate formaldee hyde discharge agent having analkalinereac-' tlon.

8., Process for the production of white discharge printing effects upona textile material comprising cellulose acetate dyed with a dyestufl prepared. by diazotizing 2-cyano-4-nitro-8 br0maniline and coupling saiddiaqotized amine with 2fdihydroxyethyl amino-4-aoetylaminoanisole, whichcomprises applying to said dyed material in a predetermined pattern adischarge paste com prising a sulfoxylate, formaldehyde discharge Iagent having an alkaline reaction.

' 9. Process for the production of discharge print ing effects 'upon atextile material dyed with a comprising a sulfoxyla'te formaldehydedischarge agent having an alkalinereaction and all but leuco formincorporated therein.

one 'of said compositions having ayat dye,in the 10. Process. for theproduction of discharge 7 Q printing effects upon a textile materialcompris- .ing an organic derivative of cellulose'dyedwith adyestuifprepared'by diazotizing 2-cyano-4- nitro-6-brom-aniline and. couplingsaid diamtised amine with 2-di-hydroxyethyl-amino-4-aoetylamino-anisoleto obtain a multicolored discharge pattern having both white andilluminated areas on the background, which comprises applying to saiddyed material in a predetermined pattern a plurality of discharge pastecompositions, each comprising a'sulioxylateformalde hyde discharge agenthaving an alkaline reac-' tion and all but one oi said compositionshaving a vat dye in the leuco form incorporated therein. 11. Process forthe production of discharge printing eflects upon a textile materialcomprising'cellulose acetate dyed with a dyestufl prepared bydiazotizing 2-cyano-4-nitro-6-bromaniline and coupling said diazotizedamine with 2- a,ass,'ass

dihydroxyethyl-amino-4-acetylamino-anisole to agent having an alkalinereaction and all but one of said compositions having a vat dye in theleuco form incorporated therein. a J

12. Process for the production of dis'charge printing effects upon atextile material compris- -ing cellulose acetate dyed with a dyestuflprepared by diazotizing 2-cyano-4-nitro-B-brom-aniline and coupling saiddiazotized amine with Z-dihydroxyethyl-amino-4-acetylamino-anisole,which comprises locally applying to said dyed material in apredetermined pattern a plurality-of discharge paste compositions, eachcomprising/ sodium sulioxylate formaldehyde and all but one of saidcompositions having a vat dye in the leuco iorm incorporated therein. V

13. Process for the productionot white discharge printing effects upon atextile material comprising cellulom acetate dyed with a dyestui'!prepared by diazotizing 2-cyano-4-nitro-6-bromaniline and coupling saiddiazotized amine with 2-dihydroxyethyl-amino-4- acetylamino anisole,which comprises applying to said dyed material in a predeterminedpattern a discharge paste comprising 10 parts by weight of sodiumsulioxyl- I aniline and coupling said diazotized amine with.z-dihydroxyethyl amino-4-acetylamlno -anisole,.

to obtain a multicolored discharge pattern having both white andilluminated areas in the baciground, which comprises applyi s to saiddyed material in a predetermined pattern a plurality of discharge pastecompositions, one oi said' dis- H charge paste compositions comprising 8parts by weight or sodium sulioxylate formaldehyde, 6

parts or sodium thiocyanate, 50 parts of a'thick-' ening agent and 38parts of water, another comprising 4 parts by weight or sodiumsulioxylate formaldehyde, 4 parts of sodium thiocyanate, 4 parts 01'soda ash, 41 parts oi a thickening agent, 3 parts of Ponsol Jade Green,{parts of Ponsol Flavone G6, 4 parts oi Indanthrene Golden Yellow GKand'32 parts or water, and another 8 parts by weightoi sodiumsulioxylate iormalde-- 'hyde, 6 parts 01' sodium thiocyanate, 4 parts ofcaustic soda, 15 parts Sulphanthrene pinkl, 45 parts or a thickeningagent and 24 parts oi water.

' GEORGE W. SEYMOUR.

VICTOR 8., SALVIN.

